In optical communication systems, optical switches are used to direct optical signals along desired transmission paths or to route these optical signals around a fault in the transmission path. The transmission path is typically an optical fiber, a form of waveguide. There are many physical mechanisms for performing optical switching from one or more input waveguides to one or more output waveguides. Some key performance parameters of optical switches include their transmission losses to desired output port, cross-talk to undesired ports, switching time, physical size, scalability and cost.
It has been suggested that frustrated total internal reflection can be used in optical switching. For example, U.S. Pat. No. 6,519,382 describes an optical switch for processing an optical signal, where the switch includes an input waveguide having a reflective surface, a first output waveguide coupled to the input waveguide, and a second output waveguide. The second output waveguide has a first position spaced apart from the reflective surface of the input waveguide such that the reflective surface totally internally reflects an optical signal toward the first output waveguide. The second output waveguide has a second position in proximal contact with the reflective surface to frustrate the total internal reflection of the optical signal such that the second output waveguide receives the optical signal.